1. Field of the Invention
This invention relates in general to a slit apparatus for use in a slit illuminating optical apparatus for slit illuminating an object to be examined, or more particularly to a slit apparatus which is capable of changing or varying slit direction or width.
2. Description of the Prior Art
A slit lamp for ophthalmology or a microscope for use in performing surgical operation has a slit illuminating optical apparatus for slit illuminating an object to be examined. The slit illuminating apparatus has a slit apparatus for generating a slit light beam from light issued from a light source. The direction of rotation and width of the slit light beam must be changed, and thus a variety of slit apparatus have been proposed and carried out.
As an example of a conventional apparatus, it was known to form the apparatus with an independent knob for slit direction adjustment and an independent knob for slit width adjustment. As another example, an apparatus was known of type where the slit width is adjusted by rotating a knob for slitwidth adjustment about a drive shaft perpendicular to the light axis while the slit direction is adjusted by rotating the drive shaft about the light axis.
However, the former slit apparatus has the disadvantages that its construction is complicated and that it must be operated by two knobs which are separated from each other.
The latter slit apparatus has a disadvantage in that since the operating knob itself is rotated about the light axis and thus is not fixed, the position of the operating knob must be determined by groping for it during operation.